D.K.
Juice is unnecessary (actually the American Academy of Pediatrics recommends against it) - it is empty calories and lots of sugar. My son did not get juice until he was probably 4 and then maybe once every 3-4 months - we have never watered it down - sounds gross.
Hitting is normal, although undesirable. At this age you distract them with something they can do. So, you say, hands are for (hugging, clapping, insert whatever you like her) and then give him something he can do. Some people recommend hitting their hand - all they learn is that it is ok (for big people) to hit.
We potty trained my son at 25 months. He had zero signs of 'potty readiness'. His parents were 100% ready to get rid of diapers. We just put him in underwear, told him pee and poop went in the potty and took him in to the bathroom with us when we went so he knew what it was for. We did no rewards, stickers or excessive praise. He had it down in 3-4 days, a few accidents for the remainder of a week, probably 2 more accidents over the next 4-6 months. We just treated it as something that was expected. Just like we expected to brush his teeth with him. Make it fun but don't go over the top.